Patent GB-622463-A (GB)
Title: Improvements in or relating to the manufacture of organo silicon compounds by the grignard reaction
IPC: C08G77/06
Filed: 1946-02-13
Abstract: Condensation-polymerization products are obtained by reacting a Grignard reagent with an organo silicate which has been prepared from an alcohol containing a proportion of water corresponding to not more than one molecular proportion to three molecular proportions of alcohol, e.g. industrial alcohol containing 4 to 5 per cent of water. The organo silicate may be refluxed or fractionated before treatment with the Grignard reagent.  The Grignard reagent may be employed in the proportion of two molecules per silicon atom in the organo silicate.  The resulting substituted ester may be either hydrolysed and then fractionated, or distilled, hydrolysed and then fractionated.  In examples: (1) ethyl silicate, prepared from silicon tetrachloride and industrial alcohol containing about 5 per cent water, is reacted with magnesium and ethyl bromide, the products are poured on to ice and the substituted silicon esters obtained are distilled, hydrolysed by refluxing with sulphuric acid, and the resulting oil is fractionated; (2) as in (1) using two molecules of Grignard reagent per silicon atom in the ethyl silicate, and the product, which is a mixture of oil and resin, is rapidly distilled to remove the solvent soluble oil and the resin remaining is heated to complete curing, if necessary, in the presence of a catalyst, e.g. benzoyl peroxide; (3) an ethyl silicone resin with similar properties to that of (2) is prepared as in (1); (4) an ether soluble silicone type resin is obtained by reacting an ethyl silicate prepared by the method given in example 1 of Specification 621,742 with ethyl magnesium bromide as in (1). Specification 591,149 is referred to.ALSO:Condensation-polymerization products are obtained by reacting a Grignard reagent with an organo silicate which has been prepared from an alcohol containing a proportion of water corresponding to not more than one molecular proportion to three molecular proportions of alcohol, e.g. industrial alcohol containing 4 to 5 per cent of water. The organo-silicate may be refluxed or fractionated before treatment with the Grignard reagent.  The Grignard reagent may be employed in the proportion of two molecules per silicon atom in the organo silicate.  The resulting substituted ester may be either hydrolysed and then fractionated. In examples: (1) ethyl silicate, prepared from silicon tetrachloride and industrial alcohol containing about 5 per cent water, is reacted with magnesium and ethyl bromide, the products are poured on to ice and the substituted silicon esters obtained are distilled, hydrolysed by refluxing with sulphuric acid, and the resulting oil is fractionated; (2) as in (1) using two molecules of Grignard reagent per silicon atom in the ethyl silicate, and the product, which is a mixture of oil and resin, is rapidly distilled to remove the solvent soluble oil, and the resin remaining is heated to complete curing, if necessary, in the presence of a catalyst, e.g. benzoyl peroxide; (3) an ethyl silicone resin with similar properties to that of (2) is prepared as in (1); (4) an ether soluble silicone type resin is obtained by reacting an ethyl silicate resin prepared by the method given in example 1 of Specification 621,742, [Group IV (a)], with ethyl magnesium bromide as in (1).  Specification 591,149 also is referred to.